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  • 1
    Electronic Resource
    Electronic Resource
    New York, NY : Wiley-Blackwell
    Helvetica Chimica Acta 47 (1964), S. 174-181 
    ISSN: 0018-019X
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: If iron oxides are reduced at temperatures ranging from 300° to 500°C, Fe3O4, is first formed, if not already present, and this goes directly over into iron. The nucleation of iron is slow, and if the oxide is finely crystalline, the iron nuclei grow by diffusion of iron atoms from many oxide crystals already at a temperature of approximately 300°C. The iron crystals sinter together to form irregular secondary particles. - Responsible for the pyrophorous behaviour is the specific surface. Self-ignition occurs when this surface is greater than approximately 3 m2/g. Pyrophorous iron can be inactivated with a mixture of N2 low in 02, an oxide layer being formed approximately 13 Å, i.e. ca. 6 02--layers, thick. An estimation of the heat produced on forming this layer and of the resulting temperature increase leads to a value which is in agreement with the ignition temperature of inactivated iron powder with a specific surface of approx. 3 m2/g.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
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  • 2
    ISSN: 0018-019X
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Das 2,4,6-Trinitroresorcin ( = H2Tric) bildet ausser den bereits bekannten Bleisalzen PbTric · H2O und Pb2(OH)2 Tric noch die Verbindungen Pb5(OH)6Tric2 und Pb13O7(OH)8Tric2. Diese Niederschläge wurden aus Pb(ClO4)2-Lösungen durch Zugabe von NaOH und Trinitroresorcin erzeugt. Die überstehenden Lösungen waren 0,2 M an NaClO4. Nach zehnmonatiger Versuchsdauer wurde in ihnen - log[Pb]total, - log[Tric]total und - log[H+] bestimmt. Daraus wurden für die Löslichkeitskonstanten \documentclass{article}\pagestyle{empty}\begin{document}$$ - \log *L_{{\rm pb}_{\rm q}} ({\rm OH})_{2({\rm q - s})} {\rm x}_{\rm s} = - \log [{\rm pb}^{2 +}] - s/q\log [{\rm Tric}^2]^ - + 2(1 - s/q)\log [{\rm H}^ +] $$\end{document} folgende Werte bestimmt: TextBodenkörper-log*LBodenkörper-log*LPbTric · H2O5,35 ± 0,06Pb5(OH6)Tric2-1,26 ± 0,15Pb2(OH)2Tric-0,40 ± 0,25Pb13O7(OH)8Tric2-7,96 ± 0,19Pb5(OH)6Tric2-2,36PbO · Pb(OH)2-12,33 ± 0,09Die Werte der linken Spalte sind nur im Bereich - log[H+] ≤ 8,5, die der rechten nur im Bereich - log[H+] ≥ 11,0 gültig.Aus diesen Daten wurde das Prädominanzdiagramm mit den Achsen - log[H+], - log[Pb]total und - log[Tric]total gezeichnet. Das Diagramm wird bei höheren pH-Werten durch das PbO · Pb(OH)2 abgeschlossen.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
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  • 3
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Zeitschrift für die chemische Industrie 76 (1964), S. 54-54 
    ISSN: 0044-8249
    Keywords: Chemistry ; General Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
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